1989: KATHY IRELAND

When Ireland flaunted her figure on the 25th anniversary edition of SI in 1989 (left), it went on to become the best-selling issue of its time. She appeared on the cover again in 1992 and in 1994, when she was pregnant. Battling weight issues in the late 2000s, she got back in shape – though admitted she didn't have a desire to slip back into a bikini. Not that the 49-year-old mom would need to: In 2012, she was deemed the world's richest supermodel by Forbes, worth $350 million thanks to her clothing and home lines and her stint on Dancing with the Stars.